T1 pelvic angle: a new predictor for postoperative sagittal balance and clinical outcomes in adult scoliosis.

Abstract

A retrospective radiographical study. To compare the prediction abilities of T1 pelvic angle (TPA) and other parameters for postoperative sagittal balance, and investigate the relationships between these parameters and health-related quality of life. Using sagittal vertical axis (SVA) to assess sagittal alignment fails to take account of the pelvic compensation. A new parameter, TPA, has been recommended to represent the global sagittal balance of adult scoliosis. A retrospective review was performed on patients with adult scoliosis undergoing correction surgery from May 2009 to March 2013. The Spearman ρ was used to determine the correlations between the radiographical parameters (preoperative, postoperative, and changes) and the overall Oswestry Disability Index (ODI), visual analogue scale (VAS), and Scoliosis Research Society-22 (SRS-22) questionnaire scores. Significant correlations were found between the changes of TPA and the changes of lumbar lordosis, pelvic tilt, sacral slope, pelvic incidence, SVA, spinosacral angle, ODI, VAS, SRS-22, and pedicle subtraction osteotomy (PSO) degrees (P < 0.05). The changes of SVA were significantly related to the changes of lumbar lordosis, TPA, C7-sacrofemoral distance, ODI, VAS, SRS-22 (P < 0.05) but not PSO degrees (P > 0.05). Significant correlations were found between the changes of spinosacral angle and the changes of thoracolumbar kyphosis, TPA, ODI, VAS, SRS-22, and PSO degrees (P < 0.05). The changes of C7 plumb line to sacrofemoral distance ratio were significantly related to the changes of SVA (P < 0.05), but not the changes of ODI, VAS, SRS-22, or PSO degrees (P > 0.05). TPA could better reflect the postoperative changes of sagittal alignment and health-related quality of life for patients with adult scoliosis. Moreover, the changes of TPA are strongly correlated to the osteotomy degrees for PSO and, TPA could be used as a reference parameter in surgical planning. 4.